The present invention relates to a connecting link between the rotor and the cam plate of a variable displacement swash plate compressor.
As shown in FIG. 1, there is known a connecting link between a rotor 2 supported by a driving shaft 1 to rotate synchronously with the driving shaft 1 and a variable inclination cam plate 3 supported by the driving shaft 1 of a variable displacement swash plate compressor. The cam plate 3 can incline between the minimum inclination shown in FIG. 1(a) and the maximum inclination shown in FIG. 1(b). The connecting link comprises a first arm 2a extending from the rotor 2 toward the cam plate 3 and a second arm 3a extending from the cam plate 3 toward the rotor 2. The first arm 2a is provided with an oval guide hole 2a, extending at right angles to a plane defined by the central axis 1X of the driving shaft 1 and the top dead center 3X of the cam plate 3. The second arm 3a is provided with a pin 4 extending at right angles to the plane. The pin 4 has a circular cross section and is inserted in the oval guide hole 2a7 with its circumferential side surface abutted against both the long side surface of the oval guide hole 2a7 distant from the rotor 2 and the long side surface of the oval guide hole 2a7 close to the rotor 2.
In FIG. 1(c), the abutting point of the surface of the pin 4 against the long side surface of the oval guide hole 2a7 at the minimum inclination of the cam plate 3 is indicated by a solid triangle, while the abutting point of the surface of the pin 4 against the long side surface of the oval guide hole 2a7 at the maximum inclination of the cam plate 3 is indicated by an open triangle. As seen from FIG. 1(c), the abutting point indicated by the solid triangle is close to the abutting point indicated by the open triangle. Therefore, a quite narrow region of the surface of the pin 4 abuts repeatedly against the long side surface of the oval guide hole 2a7 following the fluctuation of the inclination of the cam plate 3.
High contact pressure is generated at the abutting point between the surface of the pin 4 and the long side surface of the oval guide hole 2a7 close to the rotor 2 because a thrust force is transmitted from the cam plate 3 to rotor 2 during the operation of the compressor. Therefore, if the quite narrow region of the surface of the pin 4 abuts repeatedly against the long side surface of the oval guide hole 2a7 close to the rotor 2 following the fluctuation of the inclination of the cam plate 3, the surface of the pin 4 in the narrow region is rapidly worn away, the pin 4 rapidly wears out, and the connecting link rapidly wears out.
As shown in FIG. 2, there is known a connecting link between a rotor 12 supported by a driving shaft 11 to rotate synchronously with the driving shaft 11 and a variable inclination cam plate 13 supported by the driving shaft 11 of a variable displacement swash plate compressor.
The cam plate 13 can incline between the minimum inclination shown in FIG. 2(a) and the maximum inclination shown in FIG. 2(b). The connecting link comprises a first arm 12a extending from the rotor 12 toward the cam plate 13 and a pin 14 extending from the cam plate 13 toward the rotor 12. The first arm 12a is provided with a guide hole 12a7 extending parallel to a plane defined by the central axis 11X of the driving shaft 11 and the top dead center 13X of the cam plate 13. The pin 14 is provided with a ball 14a at its tip. The pin 14 is inserted in the guide hole 12a7 with the ball 14a abutted against the side surface of the guide hole 12a7.
In FIG. 2(c), the abutting point of the surface of the ball 14a against the side surface of the guide hole 12a7 at the minimum inclination of the cam plate 13 is indicated by a solid triangle, while the abutting point of the surface of the ball 14a against the side surface of the guide hole 12a7 at the maximum inclination of the cam plate 13 is indicated by an open triangle. As seen from FIG. 2(c), the abutting point indicated by the solid triangle is close to the abutting point indicated by the open triangle.
Therefore, a quite narrow region of the surface of the ball 14a abuts repeatedly against the side surface of the guide hole 12a7 following the fluctuation of the inclination of the cam plate 13.
High contact pressure is generated at the abutting point between the surface of the ball 14a and the side surface of the guide hole 12a7 close to the rotor 12 because a thrust force is transmitted from the cam plate 13 to rotor 12 during the operation of the compressor. Therefore, if the quite narrow region of the surface of the ball 14a abuts repeatedly against the side surface of the guide hole 12a7 close to the rotor 12 following the fluctuation of the inclination of the cam plate 13, the surface of the ball 14a in the narrow region is rapidly worn away, the ball 14a rapidly wears out, and the connecting link rapidly wears out.
An object of the present invention is to provide a connecting link between the rotor and the cam plate of a variable displacement swash plate compressor superior in durability to the conventional connecting link.
In accordance with one aspect of the present invention, there is provided a connecting link between a rotor supported by a driving shaft to rotate synchronously with the driving shaft and a variable inclination cam plate supported by the driving shaft of a variable displacement swash plate compressor, comprising a first arm extending from the rotor toward the cam plate and a second arm extending from the cam plate toward the rotor, wherein the first arm is provided with an oval guide hole extending at right angles to a plane defined by the central axis of the driving shaft and the top dead center of the cam plate, the second arm is provided with a pin extending at right angles to the plane, the pin has a sector-shaped cross section with rounded apex, and the pin is inserted in the oval guide hole with the apex of the sector-shaped cross section abutted against the long side surface of the oval guide hole distant from the rotor and the circular arc portion of the sector-shaped cross section abutted against the long side surface of the oval guide hole close to the rotor
In the connecting link of this aspect of the present invention, the cross section of the pin inserted into the oval guide hole of the rotor is sector-shaped. Therefore, the radius of curvature of the circular arc portion of the sector-shaped cross section of the pin inserted into the oval guide hole (with the circular arc portion abutted against the long side surface of the oval guide hole close to the rotor) can be made larger than that of the circular cross section of the pin of the conventional connecting link shown in FIG. 1.
In the connecting link of this aspect of the present invention, the radius of curvature of the circular arc portion of the sector-shaped cross section of the pin is larger than that of the circular cross section of the pin of the conventional connecting link shown in FIG. 1. Therefore, the distance between the abutting point of the surface of the pin against the long side surface of the oval guide hole close to the rotor at the minimum inclination of the cam plate and the abutting point of the surface of the pin against the long side surface of the oval guide hole close to the rotor at the maximum inclination of the cam plate is larger than that of the conventional connecting link shown in FIG. 1. Thus, the region of the surface of the pin abutting repeatedly against the long side surface of the oval guide hole close to the rotor following the fluctuation of the inclination of the cam plate is larger than that of the conventional connecting link.
High contact pressure is generated at the abutting point between the surface of the pin and the long side surface of the oval guide hole close to the rotor because a thrust force is transmitted from the cam plate to rotor during the operation of the compressor. However, the wear of the surface of the pin of the present connecting link is less than that of the conventional connecting link shown in FIG. 1, the durability of the pin of the present connecting link is greater than that of the conventional connecting link shown in FIG. 1, and the durability of the present connecting link is greater than that of the conventional connecting link shown in FIG. 1, because the region of the surface of the pin of the present connecting link abutting repeatedly against the long side surface of the oval guide hole close to the rotor following the fluctuation of the inclination of the cam plate is larger than that of the conventional connecting link.
The apex of the sector-shaped cross section of the pin of the present connecting link abuts against the long side surface of the oval guide hole distant from the rotor. However, no high contact pressure is generated at the abutting point between the apex of the sector-shaped cross section of the pin and the long side surface of the oval guide hole distant from the rotor because the apex of the sector-shaped cross section of the pin is forced in the direction apart from the long side surface of the oval guide hole distant from the rotor. Moreover, the apex of the sector-shaped cross section of the pin is rounded. Therefore, no excessive wear is generated on the apex of the sector-shaped cross section of the pin.
In accordance with another aspect of the present invention, there is provided a connecting link between a rotor supported by a driving shaft to rotate synchronously with the driving shaft and a variable inclination cam plate supported by the driving shaft of a variable displacement swash plate compressor, comprising a first arm extending from the rotor toward the cam plate and a second arm extending from the cam plate toward the rotor, wherein the first arm is provided with a guide groove extending parallel to a plane defined by the central axis of the driving shaft and the top dead center of the cam plate, the second arm is provided with a tip whose shape as viewed from the side is a sector with rounded apex, and the tip of the second arm is inserted in the guide groove with the apex of the sector abutted against the side surface of the guide groove distant from the rotor and the circular arc portion of the sector abutted against the side surface of the guide groove close to the rotor.
In the connecting link of this aspect of the present invention, the second arm is provided with a tip of sector shape in side view. Therefore, the radius of curvature of the circular arc portion of the sector of the tip inserted into the guide groove (with the circular arc portion abutted against the side surface of the guide groove close to the rotor) can be made larger than that of the ball at the tip of the pin of the conventional connecting link shown in FIG. 2.
In the connecting link of this aspect of the present invention, the radius of curvature of the circular arc portion of the sector of the tip of the second arm is larger than that of the ball at the tip of the pin of the conventional connecting link. Therefore, the distance between the abutting point of the surface of the circular arc portion of the sector of the tip of the second arm against the side surface of the guide grove at the minimum inclination of the cam plate and the abutting point of the surface of the circular arc portion of the sector of the tip of the second arm against the side surface of the guide groove at the maximum inclination of the cam plate is larger than the distance between the abutting points of the surface of the ball at the tip of the second arm of the conventional connecting link shown in FIG. 2. Thus, the region of the surface of the circular arc portion of the sector of the tip of the second arm abutting repeatedly against the side surface of the guide groove following the fluctuation of the inclination of the cam plate is larger than the repeatedly abutting region of the surface of the ball at the tip of the second arm of the conventional connecting link shown in FIG. 2.
High contact pressure is generated at the abutting point between the surface of the circular arc portion of the sector of the tip of the second arm and the side surface of the guide groove close to the rotor because a thrust force is transmitted from the cam plate to rotor during the operation of the compressor. However, the wear of the surface of the circular arc portion of the sector of the tip of the second arm of the present connecting link is less than the wear of the surface of the ball at the tip of the second arm of the conventional connecting link shown in FIG. 2, the durability of the second arm of the present connecting link is greater than that of the conventional connecting link shown in FIG. 2, and the durability of the present connecting link is greater than that of the conventional connecting link shown in FIG. 2, because the region of the surface of the circular arc portion of the sector of the tip of the second arm of the present connecting link repeatedly abutting against the side surface of the guide groove close to the rotor following the fluctuation of the inclination of the cam plate is larger than the region of the surface of the ball at the tip of the pin of the conventional connecting link shown in FIG. 2.
The apex of the sector of the tip of the second arm of the present connecting link abuts against the side surface of the guide groove distant from the rotor. However, no high contact pressure is generated at the abutting point between the apex of the sector of the tip and the side surface of the guide groove distant from the rotor because the apex of the sector of the tip of the second arm is forced in the direction apart from the side surface of the guide groove distant from the rotor. Moreover, the apex of the sector of the tip of the second arm is rounded. Therefore, no excessive wear is generated on the apex of the sector of the tip of the second arm.
In accordance with another aspect of the present invention, there is provided a connecting link between a rotor supported by a driving shaft to rotate synchronously with the driving shaft and a variable inclination cam plate supported by the driving shaft of a variable displacement swash plate compressor, comprising a first arm extending from the rotor toward the cam plate and a second arm extending from the cam plate toward the rotor, wherein the first arm is provided with a guide hole extending parallel to a plane defined by the central axis of the driving shaft and the top dead center of the cam plate, the second arm is provided with a tip whose shape as viewed from the side is a sector with rounded apex, and the tip of the second arm is inserted in the guide hole with the apex of the sector abutted against the side surface of the guide hole distant from the rotor and the circular arc portion of the sector abutted against the side surface of the guide hole close to the rotor.
In the connecting link of this aspect of the present invention, the second arm is provided with a tip of sector shape in side view. Therefore, the radius of curvature of the circular arc portion of the sector of the tip inserted into the guide hole (with the circular arc portion abutted against the side surface of the guide hole close to the rotor) can be made larger than that of the ball at the tip of the pin of the conventional connecting link shown in FIG. 2.
In the connecting link of this aspect of the present invention, the radius of curvature of the circular arc portion of the sector of the tip of the second arm is larger than that of the ball at the tip of the pin of the conventional connecting link shown in FIG. 2. Therefore, the distance between the abutting point of the surface of the circular arc portion of the sector of the tip of the second arm against the side surface of the guide hole close to the rotor at the minimum inclination of the cam plate and the abutting point of the surface of the circular arc portion of the sector of the tip of the second arm against the side surface of the guide hole close to the at the maximum inclination of the cam plate is larger than the distance between the abutting points of the surface of the ball at the tip of the second arm of the conventional connecting link shown in FIG. 2. Thus, the region of the surface of the circular arc portion of the sector of the tip of the second arm abutting repeatedly against the side surface of the guide hole close to the rotor following the fluctuation of the inclination of the cam plate is larger than the repeatedly abutting region of the surface of the ball at the tip of the second arm of the conventional connecting link shown in FIG. 2.
High contact pressure is generated at the abutting point between the surface of the circular arc portion of the sector of the tip of the second arm and the side surface of the guide hole close to the rotor because a thrust force is transmitted from the cam plate to rotor during the operation of the compressor. However, the wear of the surface of the circular arc portion of the sector of the tip of the second arm of the present connecting link is less than the wear of the surface of the ball at the tip of the second arm of the conventional connecting link shown in FIG. 2, the durability of the second arm of the present connecting link is greater than that of the conventional connecting link shown in FIG. 2, and the durability of the present connecting link is greater than that of the conventional connecting link shown in FIG. 2, because the region of the surface of the circular arc portion of the sector of the tip of the second arm of the present connecting link repeatedly abutting against the side surface of the guide hole close to the rotor following the fluctuation of the inclination of the cam plate is larger than the region of the surface of the ball at the tip of the pin of the conventional connecting link shown in FIG. 2.
The apex of the sector of the tip of the second arm of the present connecting link abuts against the side surface of the guide hole distant from the rotor. However, no high contact pressure is generated at the abutting point between the apex of the sector of the tip and the side surface of the guide hole distant from the rotor because the apex of the sector of the tip of the second arm is forced in the direction apart from the side surface of the guide hole distant from the rotor. Moreover, the apex of the sector of the tip of the second arm is rounded. Therefore, no excessive wear is generated on the apex of the sector of the tip of the second arm.